title: Unusual noncanonical intron editing is important for tRNA splicing in Trypanosoma brucei.
abstract: In cells, tRNAs are synthesized as precursor molecules bearing extra sequences at their 5' and 3' ends. Some tRNAs also contain introns, which, in archaea and eukaryotes, are cleaved by an evolutionarily conserved endonuclease complex that generates fully functional mature tRNAs. In addition, tRNAs undergo numerous posttranscriptional nucleotide chemical modifications. In Trypanosoma brucei, the single intron-containing tRNA (tRNA(Tyr)GUA) is responsible for decoding all tyrosine codons; therefore, intron removal is essential for viability. Using molecular and biochemical approaches, we show the presence of several noncanonical editing events, within the intron of pre-tRNA(Tyr)GUA, involving guanosine-to-adenosine transitions (G to A) and an adenosine-to-uridine transversion (A to U). The RNA editing described here is required for proper processing of the intron, establishing the functional significance of noncanonical editing with implications for tRNA processing in the deeply divergent kinetoplastid lineage and eukaryotes in general.
authors.affiliation: Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Mary Anne T
authors.initials: MA
authors.lastname: Rubio
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Paris
authors.forename: Kirk W
authors.initials: KW
authors.lastname: Gaston
authors.forename: Ian M C
authors.initials: IM
authors.lastname: Fleming
authors.forename: Paul
authors.initials: P
authors.lastname: Sample
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Trotta
authors.forename: Juan D
authors.initials: JD
authors.lastname: Alfonzo
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism; D007438:Introns / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D017393:RNA Editing; D034622:RNA Interference; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012326:RNA Splicing; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D012365:RNA, Transfer, Tyr / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins; D012322:RNA Precursors; D016053:RNA, Protozoan; D012365:RNA, Transfer, Tyr; D004722:Endoribonucleases; C051012:splicing endonuclease